Pipes or duct work in dwellings, commercial buildings and industrial plants are used for heating or air conditioning purposes and therefore carry fluids, such as heated or cooled air, or steam. In industrial applications, pipes or duct work also may carry chemicals or petroleum products or the like. Such pipes our duct work and associated heating or air conditioning units typically are covered with an exterior layer of insulation. The duct work typically is formed of aluminum or steel, while the pipes may be formed of any suitable material, such as copper, steel, aluminum, plastic, rubber or other like materials.
The insulation used to cover such pipes or duct work and associated heating and air conditioning units often includes fiberglass or mineral wool, foamed cellular glass or a rigid foam, covered by a jacket of foil or a layer of paper, such as kraft paper. Other layers of materials may be included in the insulation jacket, such as a layer of foil, a scrim, or a layer of polyester. Duct board is often used to cover duct work.
When such pipes or duct work are in a location exposed to weather or when they are in other environments where the exterior insulation surface is subject to degradation by moisture or the like, it is common to cover the insulation with a facing. This is particularly true for insulation having an exterior layer of paper or for duct board, (whether or not the surface is a metalized layer or a paper layer) to protect the insulation from moisture, sun, wind or other weather elements.
In one existing example, sheet metal cladding is applied to the exterior surface of the insulation. Such cladding typically is formed of aluminum, stainless steel, galvanized steel, or another like metal. This cladding has certain drawbacks including the fact that such cladding is very expensive and time consuming to install. In addition, metal cladding is not water or vapor tight or weatherproof because of joints, any repairs can be quite costly, prefabrication of the cladding is required off site, and metal cladding is very heavy and therefore difficult to handle.
Another existing solution is to cover the insulation with butyl rubber. However, this solution also has drawbacks including the fact that the butyl rubber does not perform well and tends to delaminate, particularly in extreme weather conditions. Butyl rubber also is very difficult to apply because it is messy to cut and form, and it is very heavy. Moreover, butyl rubber has been known to cause delamination of the outer surface of the insulation from the fiberglass or the wool disposed in the interior because of its weight and because of its lack of strength at elevated temperatures. A butyl rubber covering tends to have a poor appearance, and does not perform well at temperatures below zero degrees Fahrenheit or above 120° Fahrenheit and therefore should not be used in extreme weather environments where such exterior coverings are most desired and are often necessary. Butyl rubber also tends to creep, has a poor fire and smoke rating, and therefore is not UL listed. Finally, solvents are required to activate butyl rubber at temperatures below 45° F.
It is also known to cover insulation with thin layers of aluminum foil using a butyl rubber adhesive. However, such coverings have little or no puncture resistance and the adhesive layer has the same drawbacks noted above, including a tendency to run or ooze at elevated temperatures.
Scrim and mastics are also used to cover insulation. However, the use of such materials often is very labor intensive and requires a multiple step process. These products can only be applied during certain weather conditions, and it is very difficult to regulate the thickness of mastic to make it uniform. Consequently, such products have very limited applications, and generate a poor appearance.
Another known product is bitumen felt and netting. This product is very labor intensive to apply and is not recommended for exterior use. It also has a very poor fire rating, and is unsightly. Thus, its use is very limited.
In view of the foregoing, there exists a need for a material or facing for covering insulation, particularly exterior insulation, that is relatively inexpensive, easy to apply, provides a good appearance and provides the desired vapor and weather seal. There also is a need for a product which is fire resistant, has low maintenance costs and can be used in extreme temperature conditions.